Aging is associated with an increased incidence of Type 11 diabetes mellitus. On looking at the characteristics of the age-related decline in insulin secretion that occurs with aging, it appears that the abnormality in insulin secretion that occurs in diabetes is an exaggeration of normal aging processes, coupled with increasing demand for insulin release in the setting of insulin resistance. Of great interest is the new information tha these changes can be reversed. We treated young (6 months) and old (23 months) Wistar rats with an infusion of human recombinant GLP-1 (1.5 pmol per kg body weight per minute) using an ALZET osmotic pump (1003D) implanted subcutaneously in the neck for 48 hours. Insulin mRNA was increased 3 fold in the GLP-1 infused animals. Even the old rats, which have a lower amount of mRNA (50% lower) for insulin than young rats, had a 3 fold increase in insulin mRNA. The abnormality in the insulin secretion with aging was also normalized by this treatment. Of great interest is the fact that beta cells can be induced to proliferate and perhaps new beta cells can be derived from precursor cells by stimulation with GLP-1.